Embodiments of the invention described herein relate to differential systems for motor vehicles and, more particularly, to a method for controlling axle shaft endplay in a differential assembly.
In conventional drivelines, particularly those for rear wheel drive vehicles, left-hand and right-hand semi-float axle shafts extend laterally from a differential mechanism that includes side bevel gears in continuous meshing engagement with differential pinions supported rotatably on a pinion shaft carried on a differential carrier. The differential carrier is driven rotatably by a set of meshing bevel gears, one of which is driven by a drive shaft disposed substantially perpendicular to the axle shafts. The side bevel gears typically are connected rotatably to the axle shafts by a spline connection formed on a first shoulder near the inboard ends of the axle shafts. Each axle shaft carries a second shoulder proximate its axially innermost extremity, the second shoulder located adjacent the differential pinion shaft or cross pin.
Located between the shoulders on the axle shaft is an annular recess that is axially aligned with the recess formed on the corresponding side bevel gear. A retaining member (such as a C-washer or retainer ring), fitted within the recesses of the axle shaft and side bevel gear, engages the second shoulder to limit outward axial movement of the axle shaft relative to the side bevel gear. However, because the bevel gear recess that receives the retaining member is open at its axially innermost face, the retaining member may move along the shaft axis if there is clearance between the retaining member and the shaft second shoulder, and particularly if endplay exists between the innermost end of the shaft and the pinion shaft. This axial endplay permits the shaft to move along the spline connection axially inwardly toward the pinion shaft.
The end of the shaft also rubs against the pinion shaft during operation of the differential mechanism. A portion of this shaft end may be gradually worn away due to contact with the pinion shaft, thereby increasing axial end play of the shaft. In some cases, this wear is great enough to permit the shaft second shoulder to move an axial distance from the side bevel gear greater than the thickness of the retaining member. In this instance, the retaining member can fall out of the recess in the bevel gear and may no longer be positioned along the axle shaft.